The project is designed to investigate the effect of sulfonylureas and biguanides on the metabolism of cells. Particular attention is given to the actions of these drugs on fat cell metabolism with respect to the ability of sulfonylureas to act as uncouplers of oxidative phosphorylation and of biguanides as inhibitors of electron transport. The effects of these agents will be compared with those of classical inhibitors and uncouplers of oxidative phosphorylation and of drugs which affect ion transport. Since studies to date also indicate that sulfonylureas are potent anti-lipolytic agents whose action is not due to inhibition of cyclic AMP accumulation or depression of total ATP, attention will be paid to their possible effect on other aspects of the regulation of lipolysis.